1246. Predictive Factors of Treatment Failure of Methicillin-resistant Staphylococcus aureus Pneumonia: A Multicenter Prospective Observational Study
Session: Poster Abstract Session: Clinical Infectious Diseases: Respiratory Infections
Friday, October 28, 2016
Room: Poster Hall
Background: Pneumonia caused by methicillin-resistant Staphylococcus aureus (MRSA) is associated with high mortality. Investigation of clinical and microbiological factors related to treatment failure is important for the improvement of clinical outcomes.

Methods: We conducted a 2.5-year multicenter prospective-observational study in 48 medical institutions in Japan and recorded the clinical features of patients with MRSA pneumonia who received anti-MRSA antibiotics. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated from logistic regression analysis results.

Results: A total of 199 patients met the criteria. The cases consisted of 95 (47.7%) healthcare-associated pneumonia (HCAP), 76 (38.2%) hospital-acquired pneumonia (HAP), and 25 (12.6%) community-acquired pneumonia (CAP). A Pneumonia Outcomes Research Team score of IV (vs. I/II/III, OR 3.64, 95% CI 1.12–11.85, P = 0.032) was associated with treatment failure evaluated 3 days after administration of anti-MRSA antibiotics (day 3). HAP (vs. HCAP, OR 0.47, 95% CI 0.20–1.09, P = 0.077) and CAP (vs. HCAP, OR 0.24, 95% CI 0.08–0.75, P = 0.014) had lower ORs than HCAP for treatment failure at the end of treatment. All-cause 30-day mortality was 33.7% in the overall population. Moderate (vs. mild, OR 3.16, 95% CI 1.32-7.56, P=0.0097) and severe (vs. mild, OR 4.33, 95% CI 1.92-9.80, P=0.0004) IROAD severity indexes were associated with 30-day mortality. As initial therapy, 135 patients (67.8%) received vancomycin (VCM) and 36 (18.1%) received linezolid (LZD). As clinical response on day 3 was a predictor of outcome at the time of test of cure (TOC; P = 0.0095), stratified analyses were conducted. When treatment efficacy was observed on day 3, the cure rates at the TOC were 69.6% and 30.0% in the VCM- and LZD-treated groups, respectively. When treatment efficacy was not observed on day 3, the cure rates at the TOC were 32.1% and 44.4%, respectively.

Conclusion: This study demonstrated that treatment efficacy on day 3 was associated with patient outcomes at the TOC in the VCM-treated group but not in the LZD-treated group. If antimicrobial treatment of MRSA pneumonia is initiated with VCM, evaluation of treatment efficacy at an early time point (e.g., day 3) is important to improve clinical outcomes.

Taiga Miyazaki, MD1,2, Koichi Izumikawa, MD2, Hiroshi Kakeya, MD3, Hiroshi Mukae, MD1, Yuichiro Shindo, MD4, Yoshihiro Yamamoto, MD5, Katsunori Yanagihara, MD6, Kazuhiro Tateda, MD7, Kazunori Tomono, MD8, Tadashi Ishida, MD9, Yoshinori Hasegawa, MD4, Masaharu Nishimura, MD10, Yoshihito Niki, MD11, Akira Watanabe, MD12, Kazui Soma, MD13 and Shigeru Kohno, MD1, (1)Second Department of Internal Medicine, Nagasaki University Hospital, Nagasaki, Japan, (2)Division of Infectious Diseases, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan, (3)Department of Infection Control Science, Graduate School of Medicine, Osaka City University, Osaka, Japan, (4)Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan, (5)Department of Clinical Infectious Diseases, University of Toyama, Toyama, Japan, (6)Department of Laboratory Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan, (7)Department of Microbiology and Infectious Diseases, Toho University School of Medicine, Tokyo, Japan, (8)Division of Infection Control and Prevention, Osaka University, Suita, Japan, (9)Department of Respiratory Medicine, Kurashiki Central Hospital, Kurashiki, Japan, (10)First Department of Medicine, Hokkaido University School of Medicine, Sapporo, Japan, (11)Division of Clinical Infectious Diseases, Department of Medicine, Showa University, Tokyo, Japan, (12)Research Devision for Development of Anti-Infective Agents, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan, (13)Emergency Medical Center, Kitasato University Hospital, Sagamihara, Japan


T. Miyazaki, None

K. Izumikawa, None

H. Kakeya, None

H. Mukae, None

Y. Shindo, None

Y. Yamamoto, None

K. Yanagihara, None

K. Tateda, None

K. Tomono, None

T. Ishida, None

Y. Hasegawa, None

M. Nishimura, None

Y. Niki, None

A. Watanabe, None

K. Soma, None

S. Kohno, None

Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.